The present invention relates to housewares and, more particularly to vacuum cleaners.
Vacuum cleaners are almost indispensable houseware appliances for household cleaning. Such cleaners are most commonly powered by AC power from an external source. Generally, they consist of a fan or blower operative to produce a partial vacuum at an intake. Air sucked in by the partial vacuum passes through a filter bag whereby dirt particles are removed from the air stream. The filtered air is returned to the environment.
The above externally powered vacuum cleaners tend to be large and heavy. Thus, certain types of cleaning which is adapted to vacuum cleaning is not conveniently performed with them. In addition, the need for an external power source limits their use to areas where such external power sources are available.
A relatively new class of vacuum cleaner solves the problems of size, weight and power availability. Such a new class, disclosed in U.S. Pat. No. 4,209,875, the disclosure of which is incorporated herein by reference, is exemplified by a cordless, hand-held, vacuum cleaner sold under the trademark Dust Buster by the Black and Decker Corporation. The cordless condition is achieved by an internal rechargeable battery in the vacuum cleaner capable of being recharged between uses.
Hand-held vacuum cleaners cannot be used on certain surfaces such as, for example, floors without requiring the user to stoop over. Consequently, a vacuum cleaner adapted for cleaning a floor without stooping appears to extend the advantages of cordless vacuuming.
A cordless vacuum cleaner is disclosed in U.S. patent application Ser. No. 35,072 of a type having a swivelling floor tool and a telescoping handle. The telescoping handle is retained in position by a resin integral spring in a molded resin latch. It has been discovered that the integral spring tends to take a permanent set over time, thus interfering with its ability to urge its locking dogs into a latching position.